"It's pretty obvious the accident [Thursday] exposed the weakness in the evacuation from a nuclear accident," said Epstein, chairman of the TMI Alert watchdog group.

He views the incident as a "bookend" to the 2007 winter weather-related snarl that stranded hundreds for more than a day along a 50-mile stretch of Interstate 78. Both prove the potential for people getting stuck while trying to flee the area.

Epstein said emergency officials must look at possible remedies to such gridlock, and also plan to meet the medical needs of people locked in traffic. Medical issues could range from people being exposed to radiation to running out of diabetes medication as they sit in cars.

"There is no magic bullet. But to continue to plan as if these events didn't occur is irresponsible," he said.

Steve Libhart, director of the Dauphin County Emergency Management Agency, said Thursday's accident was unique in that one crash shut down multiple roadways.

Still, the slow grind in traffic could be a preview for what would happen if there was ever a need for a mass evacuation, he said.

"When you get into an evacuation scenario, you should not expect traffic to flow like it does on a normal day," Libhart said.

But emergency planners know that, he said. Those sort of potential delays are built into evacuation plans, with differing routes favored based on traffic flow and the sort of emergency faced.

It's also important to note, Libhart said, when an evacuation might not be necessary.

If there was an incident at TMI, for example, many scenarios would encourage residents to shelter in place, since a home or building offers more protection than a car. If an extreme event required evacuation, Libhart said, the weather and wind would likely dictate who would be moved and in which directions.

In the Three Mile Island accident in 1979, more than 140,000 people fled the Harrisburg area. Only pregnant women and those with small kids were actually told to leave: a group estimated at about 5,000.
FILE PHOTO: PAUL CHAPLIN, The Patriot-News

The big unknown: how people react

Others contend it's unknown how people will react, and that's cause for concern.

Following the 1979 TMI accident, for example, about 144,000 people evacuated, including many living well outside the 10-mile zone.

They did so even though there was no general evacuation order.

The only people told to evacuate were pregnant women and preschoolers within five miles -- a group numbering about 5,000.

The U.S. Government Accountability Office earlier this year issued a report citing the possible need for more planning outside the standard 10-mile emergency zone surrounding nuclear power plants.

The GAO recommended the Nuclear Regulatory Commission, which oversees disaster response plans, learn more about how people outside the 10-mile zone will react in a disaster.

The GAO said there's reason to believe 20 percent of people in nearby areas that aren't ordered to evacuate will decide to leave anyway. Their efforts to flee the area might impede those of people closer to the disaster.

Further, because they live outside the 10-mile planning zone, they are likely unaware of evacuation plans publicized within the zone, so it's unclear how they will react and whether they will follow instructions, the GAO said.

"If the public outside the zone evacuates unnecessarily at a greater rate than expected, these shadow evacuations would put additional traffic on roadways, possibly delaying the evacuation of the public inside the emergency planning zone and potentially increasing the risk to public health and safety," the GAO wrote.

The NRC, however, disagreed with the recommendation. In general, the NRC and other federal and state agencies have consistently said existing plans, which are regularly rehearsed and graded, are adequate

A need for bigger evacuation zones?

Evacuation concerns are far from new.

A 2011 investigation by the Associated Press stressed that U.S. nuclear power plants are getting older and more vulnerable to breakdown while being driven harder. Meanwhile, populations around them have grown.

It stressed the 10-mile evacuation zones have been used since 1978, despite accidents such as Chernobyl and Fukushima Daiichi in Japan that suggest the need for bigger evacuation zones.

The AP wrote "some estimates of evacuation times have not been updated in decades, even as the population has increased more than ever imagined. Emergency plans would direct residents to flee on antiquated, two-lane roads that clog hopelessly at rush hour."

But after consulting with other officials, he said TMI is regulated by the NRC, and will do whatever the NRC requires.

At the time of the TMI accident in 1979, about 135,000 people lived within 10 miles of the plant. That figure has grown to more than 225,000. And the 10-mile zone doesn't include much of Harrisburg and other highly-populated areas, where hundreds of thousand of people live.

Traffic will jam up

Dr. Martin Pietrucha, the director of Penn State's Larson Institute for Transportation, said it's important to remember that there wasn't a massive evacuation Thursday.

Traffic might have been gridlocked, but people still had to get to work, Pietrucha said. Commuters had to make it from homes on the West Shore to offices on the East Shore, and vice versa. Buses still had to take kids to school. Drivers just knew it was going to take a lot longer.

"[Thursday] was a completely different kind of problem," Pietrucha said. "You've got lots of flows going in different directions."

In an emergency evacuation, Pietrucha said, making a routine appointment doesn't matter anymore.

Everyone has a similar goal: Get away. The highway system that so failed us Thursday could become a benefit. With proper coordination, the Turnpike and Interstates 81 and 83 can each become four lane super highways leading people away from the disaster.

However, a disaster doesn't magically change ultimate highway capacity. At some point, if everyone wants to get on the road, things will jam up somewhere.

And that should be Thursday's lesson, said Elise Miller-Hooks, a civil engineering professor at the University of Maryland who has studied traffic flows in emergencies.

"[Thursday] should raise some red flags for you all," Miller-Hooks said.

In some ways, the structure of Thursday's wreck was similar to the type of event that would require a smaller-scale evacuation, like an ammonia leak. Those sorts of hazardous materials spills don't offer the lead time that, say, a hurricane does for evacuation planners. Instead, she said, people might need to get out fast.

And that's where it comes down to communication: How well can authorities re-route traffic to keep motorists away from the danger?

Authorities have become much better in recent years with social media and text alerts, she said.

Libhart, the Dauphin County emergency official, noted that drivers can sign up for text alerts from the South Central Task Force, which includes Cumberland, Dauphin, Lebanon, Perry and York counties.

As real-time traffic monitoring gets better, planners will be able to use those sorts of communications techniques to route drivers along the most efficient roads, Miller-Hooks said.

Confidence and concern over plans

Jack Murray has spent his life in the 10-mile zone in New Cumberland, where he has been president of the borough council for 37 years. He doesn't view Thursday's gridlock as evidence of potential trouble in the event of a TMI evacuation.

He believes the gridlock would have been eased had the emergency plans of local counties been activated. He has confidence in those plans, as well as in the benefits of the regular drills related to a possible TMI disaster, and believes the area is far better prepared than in 1979.

"With the TMI drills, there's a great deal of flexibility you could apply to several kinds of emergencies," he said.

Sen. Pat Vance, R-Cumberland County, said she fully supports emergency planning. But she wonders if some people more than 10 miles from Three Mile Island would pay attention to emergency plans.

FILE PHOTO: DAN GLEITER, The Patriot-News, 2011

State Sen. Pat Vance, R-Cumberland County, doesn't see a strong "correlation" between the aftermath of Thursday's accident and would would take place during a TMI evacuation.

While she said "we can't over-prepare for emergencies," she expressed confidence in existing plans. She also wonders how much could be accomplished by extending planning efforts into new areas.

"If we can do something outside the 10-mile area all the better. But I'm also realistic enough to know people outside the 10-mile area are so consumed in their daily lives they might not pay attention," she said.

For his part, Epstein, the TMI watchdog, doesn't claim to have the solution. But he argues it's irresponsible not to learn from experience, and worries that will be the case.

"We now have a track record of what can happen in Pennsylvania. Whether it's a TMI accident, a blizzard, a tanker truck fire … this happens. Why wouldn't you incorporate this into a plan?"

Note: this article was revised to reflect that Eric Epstein is the chairman of TMI Alert. The founder is Kay Pickering.

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